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2 Sheets-Sheet 1. W. G. LEVISON.

1 Electric-Lamp. No. 227,025. Patented April 27,1880

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W. G. LEVISON. Electric-Lamp 2 Sheets-Sheet 2.

N. PETiRS, PholoLilhogx-aphnr, Washinglnn, n. c.

UNITED STATES PATENT @FFICE.

V. GOOLD LEVISON, OF BROOKLYN, NEXV YORI'.

ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 227,025, dated April 27, 1880.

Application filed November 26, 1879.

To all whom, it may concern:

Be it known that I, W. GOOLD LnvIsoN, of the city of Brooklyn, in the county of Kings and State of New York, have invented a new and useful Improvement in Electric Lamps, of which the following is a specification, reference being had to the accompanying draw- 1ngs.

My invention consists of an improvement in electric lamps, in which the light is produced between two points of carbon or metal. One of the principal difficulties to be overcome in the practical use of the carbon-point electric lightis that property of the electric fluid which leads it to follow the line of least resistance. For this reason if two lights are on the circuit and the resistance offered the current in one exceeds that of the other, the first light will go out and the second alone will receive all the current, and so will it be no matter how many lamps may be on the circuit. To remedy this, and at the same time furnish a lamp which shall be cheap in construction and effective in operation, is the result sought in this invention.

Figure 1 represents an elevation of mylamp. Fig. 2 represents a sectional view on line so a, of Fig. 1. Fig. 3 represents a modification of the method of adjusting the points between which the light is formed.

A. represents a vertical rod of insulating material supported in any suitable manner. Three hollow metal cylinders, B G D, slide easily upon this rod, and may be clamped at any desired point by the thumb-screws E E B.

At the extremities of the arms F G, projecting at a right angle from the cylinders B D, the square tubes H I are fastened in such a manner that H I are brought in one perpendicular line. A square metal rod, J, slides easily within the square tube H, and also through asquare hole in the metal plate K when K is at a right angle with the rod J; or, in other words, when K is horizontal J should be as light'as possible, yet have enough metal to carry the current without heating. The end of the metal plate K more distant from the vertical rod A rests in a metal stirrup, L, secured to the square tube H, while the other end of K rests on the spring M, so that when the plate K is horizontal the square rod J easily slips through it; but should the spring M tilt up the end of K in contact with it, then the whole is no longer horizontal, and the rod J binds therein and is sustained.

Near the end of the spring end M a plate of iron, I), is attached, which is the armature of the electro-magnet N. This magnet is supported by the arm 0, which projects from and is attached to the same cylinder, 0, that carries the spring M, so that the two together form a system which can be adjusted by the thumb-screw E at any height on the rod A.

In the square tube I the carbon point P is fastened by the thumb-screw R, or in any other suitable manner.

The spring M is constructed of a compound bar of iron and brass, steel and brass, or platinum and silver, or of any two metals which expand unequally, riveted, brazed, or otherwise fastened together. These metals are preferably such as have a comparatively low conducting power, since they are to be heated and expanded by the current which produces the light.

I have used and prefer steel and brass. In my lamp the metal expanding most goes underneath the other when the spring is in position.

The spring M is bent spirally, as shown, in order to save room, with the metal possessing the greater expansibility inside. The spiral form given M is also favorable to the action as a spring. At the pointn of the hollow cylinder C is hinged a copper rod or wire, m, ter minating in a piece formed to connect with any point of the coils of the spring ill. This serves as a regulator, so that if the spring M is found to expand too much the current may be transferred to any point to the wire or rod m. The practical result of this will be to shorten the spring and consequently lessen its expansion. Since the spring M is to be heated by the passage of the current its thickness depends upon the strength of the current used, and it must be so proportioned thereto that the current will encounter some resistance and develop some heat in its passage through its spring, but not enough to raise the temperature to near redness.

With a battery of thirty and forty cups of Bunsen l have found a spring composed of brass and steel three-thirty-seconds of an inch cross -scction and one foot long to answer. By trials with the proposed current of square rods of the better conducting metal of which the spring is composed, of different sizes, one will easily be found which will be affected as aforesaid. ll then the area of this cross-section be reproduced in the compound springit will. answer all practical purposes.

A wire from one side of the electro-n'lagnet N N leads to and connects wit-l1 the metal column S, to the top of which a spring, T, is fast ened. The other end of this spring carries an armature, U, which is over the poles of the electroanagnet 'V.

Over the spring, and in contact when the magnet V is not in actlon, is a metal thumbscrew, \"V, which passes through a metal extension erected on the metal column K. A conductingwire is attached to X, which leads to one pole of a small battery, Y, whilefrom its other pole a wire leads to the opposite pole of the electro-magnet N.

The current which is to produce the light startsfrom the positive pole of the battery Z,

and passes along the wire as x to the screw-cup which connects it at (I, through G, with the lower carbon. The current passes between the carbons, ascends the rod J, and passes through K to and through the entire length of the spring M till. it reaches the cylinder 0; thence it passes through the wire to and around the magnet V, and thence to the op posite pole of the battery Z.

In order to avoid the adherence of the armatures to the magnets through residual magnetism after the circuit is broken, the poles of the magnets should be covered with some nonmagnetic substance. Ilatinunrfoil soldered on is usually used for this purpose.

Having now described the component parts of my lamp, I will proceed to the method of its operation.

Vhen the light is burning the magnet V holds down the armature U, thereby breaking the contact at \V betweeen the magnet N and its small battery Y. N is therefore powerless. The plate K therefore rests on the end of the spring M, which tilts the contact end of K upward, and thus binds the rod J and its carbon and supports it, as hereinbefore explained. The spring M then becomes heated by the current and expands. This lifts the plate K, and with it the rod J and its carbon, in proportion as M expands.

It is apparent, therefore, that M performs two duties. The firstthat of a springis to raise the rod J and separate the carbons alter they have been brought in contact by the action of the magnet N. This could be done by any form of spring, and, with a good ade quate current and a single lamp, a spring of a single metal will answer pretty well. In brief, the function of M as a spring answers to a coarse adjustment of the eompoulul microscope, while the second dutyis that performed. by the differential expansion of the two metals composing the spring, and the consequent bending of the same answers to the final. ad justment of the same instrument. It now the current be interrupted by waste of the carbons, the magnet V ceases to act. the spring T will rise, and, making contact with the point IV, the circuit of the battery Yis complete. Themagnct Nis then excited, and instantly attacks its armature I) and brin down the end of the spring M. The end of the plate K resting on M drops with it, and as K becomes horizontal the red (I and its carbon drop until in contact with the carbrm l. instantly the primary current is reestablished. The magnet V again attracts-its armature and breaks the circuit of the small battery at the point \V. The magnet N then ceases to act, and the spring M first tilts and then lifts the plate K, and with it the rod J, thereby scparat ing the carbons and renewing the light.

In large lights, or where a number of lights are in circuit, it will be well to introduce the wire 6, which is firmly fixed to the spring M, (or its armature 1),) and is carried up and bent over into a cup of mercury placed at g. This gives a free passage to the current through .l and II to M via 0 instead of through the plate K, and consequently certainty of electrical contact between K and M is no longer material. It also prevents the heating, expansion, and possible sticking of the rod l where it passes through the plate K, and the necessity of readjusting the plate alter the light is in operation.

Under like conditions and for the same reasons a cup filled with mercury, I, may be attached to II and a bent wire led from (I into it; or J may be hollow and of iron and lilled with mercury, and a wire from H lead into it; or a tongue of spring metal may be used, attached to one and bearing lightly against the other part to be connected, instead of the mercury cups and wires.

One small battery,Y, and its magnet V will serve for any number of lamps in the samedirect circuit, and it may be at any distance from the lamps, so that its clicking need not be an annoyance; but if the poles are covered with a soft substance, such as felt, the sound may be stopped. The pole at the magnet N may also be covered for the same purpose.

Instead of the tilting plate K, the device.

shown in Fig. 3 may be used, and, though not so simple, is equally effective, and I claim it as an equivalent.

Referring to Fig. 3, the rod .l is provided with a .rack, in which the pawl L catches when the sprin M is in its normal position. This pawl is hinged to the end of the spring M at O, and it passes between the metal guides l fixed to opposite sides olthe square tube lLand is pressed against the roller or wheel IR by the spring 7:. A. portion of II is cut away, so as to Then permit the pawl to reach the rack. The roller of wheel B may revolve freely between the guides 1". The hinge joint connecting the pawl and the-end of the spring M is so constructed that by withdrawing a pin passing through the ends of the spring and pawl, and by replacing it through other holes of the series at L, the pawl may be raised or lowered.

The mode of operation of this substitute is as follows: The pawl L must first be adjusted so that when the carbons are touching and the armature I) of the magnet N is pressed down by hand the pawl will just clear the rack. If new the spring end M be allowed to resume its normal position, the pawl will catch the rack and lift the rod. So long as the current passes, the height of the rod J, and consequently the space between the carbon points, will vary with the temperature of the spring. It now the carbon points be worn away and the current be broken, the magnet N attracts the armature I) and pulls down the spring M,

and with it the pawl L. The pawl then is drawn over the roller R, and from the peculiar shape of the bearing-edge of the pawl shown in the drawings it is freed from the rack. The rod J then drops by its own weight and re establishes the current. The magnet N then ceases to act, and the spring M lifts the pawl, which again catches in the rack and lifts the rod J, thereby reproducing the light.

Of course, in the use of my invention, I do not intend to limit myself to the use of electricity generated by a battery, and when in this specification the word battery as the source of the current is used it is intended to include any suitable electric current, however generated.

I lay no claim in this application to the spring M, constructed of a compound bar of iron and port the armature of the electro-magnet and the carbon-holder.

2. in an electric lamp, the combination of an eleetro-magnet, a compound spring or bar composed of two metals of unequal expansibility and acting to support the clamping plate, (or equivalent device, hereinbefore described, and shown in Fig. 3,) the armature of said electromagnet, and the carbon-holder.

3. The connection of the eompoundspring (or the armature attached thereto) with the carbon-holder and its case or guide by means of a mercury-cup and wire, so as to form a sec 0nd or safety circuit passing from said spring or armature to the carbon-holder.

l. The wire m, so arranged that one end may be connected with any point of the compound spring or bar M and the other end may be connected with the return wire of the circuit to regulate the effective length of said com.- pound spring or bar, as hereinbefore described.

5. The connection of the carbon-holder and mercury-cup attached to its ease or guide by means of a wire, so as to form a second or safety circuit passing from the earboirholder to its case or guide.

6. The combination of a battery independent of the main circuit, an electro-magnet and its armature, and the compound or simple bar or spring M, as and for the purpose described.

In testimony that I claim the foregoing 1mprovement in electric lamps, as above described, I have hereunto set my hand this 22d day of November, 1875).

\V. GOOLD LEVlSON.

\Vitnesses:

lfIENRY P. \VELLs, L01 CLARKE ALSTON. 

